The invention relates to a telecommunication network.
The switching of stored switching data which describe the most favorable route determined on the basis of definable functions, is a known feature in a telecommunication network. More particularly, these switching data can be determined on the basis of costs. This "least cost routing" (LCR) is a known performance feature for a telecommunication network which comprises a private branch exchange for switching functions and a plurality of subscriber terminals connected to the private branch. The route causing the least operating costs for a communication to an external subscriber terminal i.e. situated outside the telecommunication network, is determined with the aid of LCR.
U.S. Pat. No. 5,452,351 has disclosed such a private branch exchange having an LCR function. The network comprises a private branch exchange to which are assigned a plurality of subscriber terminals. The private branch exchange comprises a circuit for switching functions. Furthermore, the private branch exchange is assigned a controller which comprises storage means and processing circuits for LCR functions. An input/output device (terminal), which has a keypad for entering data and an LCD display device for reading data is connected to the controller. LCR data are applied to the controller by the input/output device and are stored in the storage means. If a call from the private telecommunication network to an external subscriber is generated by a subscriber terminal, the controller will determine the route to the called other subscriber which has the least operating costs per time interval on the basis of the LCR data stored in this controller.
LCR data are stored in tables in the storage means. Codes which are called up at an external subscriber when a call is generated and which determine the least cost route to the external subscriber are stored under specific addresses. Start and end of the route are determined by the call numbers of the calling internal subscriber and of the called external subscriber.